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Diffstat (limited to 'libbb')
-rw-r--r--libbb/copyfd.c87
1 files changed, 56 insertions, 31 deletions
diff --git a/libbb/copyfd.c b/libbb/copyfd.c
index eda2747f9..7e3531903 100644
--- a/libbb/copyfd.c
+++ b/libbb/copyfd.c
@@ -8,6 +8,20 @@
*/
#include "libbb.h"
+#if ENABLE_FEATURE_USE_SENDFILE
+# include <sys/sendfile.h>
+#else
+# define sendfile(a,b,c,d) (-1)
+#endif
+
+/*
+ * We were using 0x7fff0000 as sendfile chunk size, but it
+ * was seen to cause largish delays when user tries to ^C a file copy.
+ * Let's use a saner size.
+ * Note: needs to be >= max(CONFIG_FEATURE_COPYBUF_KB),
+ * or else "copy to eof" code will use neddlesly short reads.
+ */
+#define SENDFILE_BIGBUF (16*1024*1024)
/* Used by NOFORK applets (e.g. cat) - must not use xmalloc.
* size < 0 means "ignore write errors", used by tar --to-command
@@ -18,12 +32,13 @@ static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
int status = -1;
off_t total = 0;
bool continue_on_write_error = 0;
-#if CONFIG_FEATURE_COPYBUF_KB <= 4
+ ssize_t sendfile_sz;
+#if CONFIG_FEATURE_COPYBUF_KB > 4
+ char *buffer = buffer; /* for compiler */
+ int buffer_size = 0;
+#else
char buffer[CONFIG_FEATURE_COPYBUF_KB * 1024];
enum { buffer_size = sizeof(buffer) };
-#else
- char *buffer;
- int buffer_size;
#endif
if (size < 0) {
@@ -31,46 +46,58 @@ static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
continue_on_write_error = 1;
}
-#if CONFIG_FEATURE_COPYBUF_KB > 4
- if (size > 0 && size <= 4 * 1024)
- goto use_small_buf;
- /* We want page-aligned buffer, just in case kernel is clever
- * and can do page-aligned io more efficiently */
- buffer = mmap(NULL, CONFIG_FEATURE_COPYBUF_KB * 1024,
- PROT_READ | PROT_WRITE,
- MAP_PRIVATE | MAP_ANON,
- /* ignored: */ -1, 0);
- buffer_size = CONFIG_FEATURE_COPYBUF_KB * 1024;
- if (buffer == MAP_FAILED) {
- use_small_buf:
- buffer = alloca(4 * 1024);
- buffer_size = 4 * 1024;
- }
-#endif
-
if (src_fd < 0)
goto out;
+ sendfile_sz = !ENABLE_FEATURE_USE_SENDFILE
+ ? 0
+ : SENDFILE_BIGBUF;
if (!size) {
- size = buffer_size;
+ size = SENDFILE_BIGBUF;
status = 1; /* copy until eof */
}
while (1) {
ssize_t rd;
- rd = safe_read(src_fd, buffer, size > buffer_size ? buffer_size : size);
-
- if (!rd) { /* eof - all done */
- status = 0;
- break;
+ if (sendfile_sz) {
+ rd = sendfile(dst_fd, src_fd, NULL,
+ size > sendfile_sz ? sendfile_sz : size);
+ if (rd >= 0)
+ goto read_ok;
+ sendfile_sz = 0; /* do not try sendfile anymore */
+ }
+#if CONFIG_FEATURE_COPYBUF_KB > 4
+ if (buffer_size == 0) {
+ if (size > 0 && size <= 4 * 1024)
+ goto use_small_buf;
+ /* We want page-aligned buffer, just in case kernel is clever
+ * and can do page-aligned io more efficiently */
+ buffer = mmap(NULL, CONFIG_FEATURE_COPYBUF_KB * 1024,
+ PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANON,
+ /* ignored: */ -1, 0);
+ buffer_size = CONFIG_FEATURE_COPYBUF_KB * 1024;
+ if (buffer == MAP_FAILED) {
+ use_small_buf:
+ buffer = alloca(4 * 1024);
+ buffer_size = 4 * 1024;
+ }
}
+#endif
+ rd = safe_read(src_fd, buffer,
+ size > buffer_size ? buffer_size : size);
if (rd < 0) {
bb_perror_msg(bb_msg_read_error);
break;
}
+ read_ok:
+ if (!rd) { /* eof - all done */
+ status = 0;
+ break;
+ }
/* dst_fd == -1 is a fake, else... */
- if (dst_fd >= 0) {
+ if (dst_fd >= 0 && !sendfile_sz) {
ssize_t wr = full_write(dst_fd, buffer, rd);
if (wr < rd) {
if (!continue_on_write_error) {
@@ -92,10 +119,8 @@ static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
}
out:
-#if CONFIG_FEATURE_COPYBUF_KB > 4
- if (buffer_size != 4 * 1024)
+ if (buffer_size > 4 * 1024)
munmap(buffer, buffer_size);
-#endif
return status ? -1 : total;
}